Coupled-Cavity semiconductor lasers under current modulation: Small-signal analysis.

The modulation characteristics such as the power response and the chirp (dynamic line broadening) of single-frequency coupled- cavity semiconductor lasers are analyzed theoretically. The model is based on the small-signal analysis of a set of generalized rate equations and neglects the lateral variations of the optical field and the carrier density in the two cavity sections. It is found that the chirp can be significantly reduced by a proper combination of the bias levels and the modulation splitting between the two sections. The chirp reduction also depends on the strength of the intercavity coupling and its phase and the best performance is achieved for the case of in-phase coupling.